ES2694672T3 - Power converter and air conditioner - Google Patents

Abstract

Power converter (20) providing power to a compressor (72) in an air conditioning apparatus (70), the power converter comprising: a rectifier (22) configured to rectify an input alternating current (AC) from a AC power source (91); a power factor corrector (25) that includes a reactor (L25a, L25b, L25c) and a switching device (Q25a, Q25b, Q25c) that switches between accumulation and discharge of energy, based on an input voltage (V1) which is emitted from the rectifier (22), inside and outside the reactor (L25a, L25b, L25c), and configured to be able to perform a power factor correction operation by raising the input voltage (V1); a power converter (28) connected to an output of the power factor corrector (25), and configured to generate output AC power (SU, SV, SW); and a controller (31g) configured to control the power factor correction operation by the power factor corrector (25), characterized in that the power factor corrector (25) includes a smoothing capacitor (26) provided next to a reactor outlet (L25a, L25b, L25c), and connected in parallel to the switching device (Q25a, Q25b, Q25c), and the controller (31g) is configured to: turn off the switching device (Q25a, Q25b, Q25c) so that the power factor correction operation is stopped, if an instantaneous voltage drop or instantaneous power failure occurs in the AC power supply (91) while the power factor corrector (25) is performing the power factor correction operation; leaving the compressor (72) running without rest, if the instantaneous voltage drop or instantaneous power failure occurs while the compressor (72) is running; leaving the power factor correction operation stopped when the AC power source (91) recovers; and allowing the power factor corrector (25) to perform the power factor correction operation, if the compressor (72) continues to run from the recovery of the AC power source (91) for a predetermined period of time. ; wherein the predetermined period of time is shorter than a time interval from recovery of the AC power supply (91) to a control start to drop a ripple component of a voltage across the smoothing capacitor ( 26).

Description

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DESCRIPTION

Energy converter and air conditioner Technical field

The present invention relates to an energy converter and, in particular, to a technique for reducing the malfunction of a switching device included in a power factor corrector. The present invention also relates to a reduction in the size and cost of the switching device.

Background of the technique

The compressors in air conditioners are powered by a motor that works as a drive source. The motor is driven by alternating current (AC) power supplied from a power converter.

A typical power converter mainly includes a rectifier, an elevator power factor corrector, and an inverter power converter, as disclosed in patent document 1. First, the rectifier rectifies a commercial voltage of CA issued from a commercial power source. The rectified voltage is raised to a desired voltage and flattened by the power factor corrector, so that the power factor of the voltage is corrected to improve. The voltage with the corrected power factor is supplied to the power converter. By using the voltage with the corrected power factor, the power converter generates AC power to drive the motor.

In addition, Patent Document 2 describes a system and method for limiting the sudden increase of input current in a switching mode power supply. The power supply comprises an input voltage detector which detects a drop in the input voltage corresponding to an input voltage loss. The power converter is coupled to the input voltage detector. The power converter, which can be a boost converter or a power factor correction converter, has a switching device that is operated according to a duty cycle. A work-cycle adjusting device is sensitive to detecting the drop in input voltage for adjusting the duty cycle of the switching device in order to limit a sudden increase in input current through the switching device. below a desired level after the input voltage returns.

In addition, the patent document 3 describes a control device, a control method and a power supply device. The control device includes a control unit, in which the control unit is configured for, when a first time, during which a level of a voltage emitted from a rectifier circuit to rectify an alternating current supplied from a supply of AC power is lower than a level of a threshold voltage, has reached a threshold time, issued a stop signal to stop an operation of a power factor correction circuit to a control circuit that controls the operation of the circuit of power factor correction.

In addition, the patent document 4 describes an abnormal power protection circuit. The anomalous power protection circuit includes a power detection unit, a voltage drop correction unit, a fall detection unit, a delay unit and a delay masking unit. Upon detecting an average input power value of a power supply, the occurrence of a voltage drop condition can be determined. The power supply includes a power factor correction unit having an output capacitor. Upon detection of the output capacitor voltage, a drop condition can be determined. When an abnormal power condition occurs, all the units of the power supply can be activated sequentially according to a delay time to protect circuit elements and a connection computer.

In addition, the patent document 5 describes a real-time voltage protection and detection circuit for PFC booster converters. The circuit for the protection of the operation of power factor correction converters (PFC) prevents conditions such as sudden increases in input voltage that, on the other hand, can cause failures and prevent an unnecessary unavailability time of the boost converter after a power failure or at startup.

In addition, the patent document 6 describes an air conditioner. The air conditioner has a low voltage detecting means for detecting whether the output voltage of an active filter is or not at a certain or higher voltage, a control means for stopping a switching operation of a switching element when the output voltage is detected by means of low voltage detection means which is the determined or lower voltage, and means for changing a detected value of an output voltage detection means.

List of references

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Patent document

Patent Document 1: Japanese Unexamined Patent Publication No. 2011-239547

Patent Document 2: US 2011/006748 A1

Patent Document 3: US 2012/195073 A1

Patent Document 4: US 2008/304195 A1

Patent Document 5: US 2005/269999 A1

Patent Document 6: JP 2003 079050 A

Summary of the invention

Technical problem

When an instantaneous voltage drop or instantaneous power failure occurs in the commercial power source while the power factor corrector is running, the output voltage from the power factor corrector decreases. However, the instantaneous voltage drop and instantaneous power failure last a very short period, so that the commercial power supply is recovered, for example, from 10 ms to 100 ms after the fall and a fault starts to occur. . Therefore, immediately after the recovery of the commercial power supply, the power factor corrector performs a power factor correction operation before the output voltage of the power factor corrector itself reaches a voltage value of defined output. Then, the power factor corrector tries to raise the output voltage to the defined output voltage value. As a result, the output voltage from the power factor corrector increases instantaneously, causing a flow of an excessive amount of current in a switching device included in the power factor corrector. This can cause malfunction of the switching device.

In view of the above background, an object of the present invention is, therefore, to reduce the malfunctioning of a switching device, included in a power factor corrector, when it arises from an instantaneous voltage drop or a power failure. instant.

Solution to the problem

A first aspect of the present invention relates to an energy converter that provides power to an air conditioning apparatus according to claim 1. The first aspect of the conversion apparatus is a rectifier (22) configured to rectify an alternating current (AC). ) input from an AC power source (91); a power factor corrector (25) including a reactor (L25a, L25b, L25c) and a switching device (Q25a, Q25b, Q25c) that switches between energy accumulation and discharge, based on an input voltage (V1) which is emitted from the rectifier (22), inside and outside the reactor (L25a, L25b, L25c), and configured to be able to perform a power factor correction operation by raising the input voltage (V1); an energy converter (28) connected to an output of the power factor corrector (25), and configured to generate output AC power (SU, SV, SW); and a controller (31g) configured to control the power factor correction operation by the power factor corrector (25). The power factor corrector (25) includes a flattening capacitor (26) provided close to a reactor outlet (L25a, L25b, L25c), and connected in parallel to the switching device (Q25, Q25b, Q25c). The controller (31g) is configured to: turn off the switching device (Q25a, Q25b, Q25c) so that the power factor correction operation is stopped, if an instantaneous voltage drop or an instantaneous power failure occurs. the AC power source (91) while the power factor corrector (25) is performing the power factor correction operation; leaving the compressor (72) running without rest, if instantaneous voltage drop or instantaneous power failure occurs while the compressor (72) is running; leave the power factor correction operation stopped when the AC power supply (91) is recovered; and allowing the power factor corrector (25) to perform the power factor correction operation, if the compressor (72) continues to run from the recovery of the AC power source (91) for a predetermined period of time .

According to the first aspect of the present disclosure, the switching device (Q25a, Q25b, Q25c) of the power factor corrector (25) is turned off when instantaneous power failure or instantaneous voltage drop occurs, so that the power factor correction operation (the lifting operation) stops. When the commercial power supply (91) is recovered, too, the power factor correction operation is suspended. Therefore, in the power factor corrector (25), the current path including the switching device (Q25a, Q25b, Q25c) is cut off. Cutting current path limits

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a temporary sudden increase of the output voltage (V2), from the power factor corrector (25), due to the power factor correction operation performed when the commercial power supply (91) is recovered, and reduces a excessive amount of current flowing in the switching device (Q25a, Q25b, Q25c). Such characteristics make it possible to limit the malfunction of the switching device (Q25a, Q25b, Q25c), contributing to a reduction in size and cost of the switching device (Q25a, Q25b, Q25c).

In the first aspect, a second aspect of the present disclosure may further comprise an output voltage detector (27) configured to detect an output voltage (V2) from the power factor corrector (25). The controller (31g) can be configured to determine the occurrence of the instantaneous voltage drop or the instantaneous power failure if a difference between (i) a target value (Vcc ref) of the output voltage to be emitted by the corrector of power factor (25) and (ii) a result of the detection (Vcc) by the output voltage detector (27) is greater than a predetermined difference (DIF).

According to the second aspect of the present disclosure, it is easily determined whether instantaneous voltage drop or instantaneous power failure has occurred, based on the difference between the target value (Vcc ref) of the output voltage and the result of the detection (Vcc) by the output voltage detector (27).

In the second aspect, a second aspect of the present disclosure may further comprise an input voltage detector (24) configured to detect the input voltage (V1). The controller (31g) is configured to determine the target value (Vcc_ref) of the output voltage (V2), based on a detection result (Vca_peak) by the input voltage detector (24). A detection period of the input voltage detector (24) is longer than a detection period of the output voltage detector (27).

When the instantaneous voltage drop or instantaneous power failure occurs, both the actual input voltage (V1) and the actual output voltage (V2) decrease. In the fourth aspect, on the other hand, the detection period of the input voltage detector (24) is longer than the detection period of the output voltage detector (27). Therefore, the occurrence of instantaneous voltage drop or instantaneous power failure raises the detection result (Vca_peak) by the input voltage detector (24) so that it is of higher value than the result of the detection ( Vcc) by the output voltage detector (27). Accordingly, the difference between the result of the detection (Vcc) by the output voltage detector (27) and the target value (Vcc ref) of the output voltage determined based on the detection result (Vca_peak) by the detector of input voltage (24) is greater than the predetermined difference (DIF). Accordingly, the controller (31g) can reliably determine the instantaneous voltage drop or the instantaneous power failure despite varying the target value (Vcc_ref) of the output voltage based on the detection result (Vca_peak) by the input voltage detector (24).

In the third aspect, the input voltage detector (24) in a fourth aspect of the present disclosure can be configured to sample a peak amplitude (V11) of the input voltage (V1), and determine the peak amplitude sampled. (V11) as the detection result (Vca_pico).

In the first aspect, a fifth aspect of the present disclosure may further comprise an input voltage detector (24) configured to detect the input voltage (V1). The controller (31g) may be configured to determine whether instantaneous voltage drop or instantaneous power failure has occurred, depending on how large or small the detection result (Vca_peak) is by the input voltage detector (24). ).

Because of these characteristics, the detection result (Vca_peak) by the input voltage detector (24) becomes smaller as soon as, for example, instantaneous voltage drop occurs, which contributes to an easy determination of instantaneous voltage drop or instantaneous power failure.

In the first aspect, in the power converter in a sixth aspect the controller (31g) can be configured to cause the power factor correction operation to stop and the ripple component of the voltage in the smoothing capacitor to fall. (26), if instantaneous voltage drop or instantaneous power failure occurs while the compressor (72) is running under overload.

If the compressor (72) is in overload when the power factor correction operation is stopped due to the occurrence of instantaneous voltage drop or instantaneous power failure, an excessive amount of current inevitably flows into, for example , the rectifier (22), accompanied by a falling power factor due to the stopping of the power factor correction operation. In the tenth aspect of the present disclosure, however, the ripple component drop control is performed in addition to stopping the power factor correction operation, if instantaneous voltage drop or instantaneous power failure occurs. when the compressor (72) is in overload. Such a feature limits the performance of the compressor (72) despite the fact that the power factor correction operation is stopped, which helps to limit the flow of the excessive amount of current into, for example, the rectifier. (22)

Advantages of the invention

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The first aspect makes it possible to limit the malfunctioning of the switching device (Q25a, Q25b, Q25c), contributing to a reduction in the size and cost of the switching device (Q25a, Q25b, Q25c).

The second aspect makes it possible to easily determine whether instantaneous voltage drop or instantaneous power failure has occurred.

The third aspect allows the controller (31g) to reliably determine the instantaneous voltage drop or instantaneous power failure despite varying the target value (Vcc_ref) of the output voltage based on the detection result (Vca_pico ) by the input voltage detector (24).

The sixth aspect allows limiting a flow of excessive amount of current into, for example, the rectifier (22).

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram of a motor drive system that includes an energy converter.

Figure 2 is a timing diagram illustrating temporary changes in: input voltage; peak amplitude of the input voltage; entry detection period; and result of detection by an input voltage detector.

Figure 3 is a schematic diagram illustrating functional units of a controller according to a first embodiment.

Figure 4 is a graph that conceptually illustrates a variable output target value according to the first embodiment.

Figure 5 is a timing diagram illustrating temporary changes in: input voltage; detection results by an input voltage detector and an output voltage detector; permission and prohibition of a power factor correction operation by a power factor corrector; PFC drive instruction signal; output state of a power factor correction actuator; PFC current; and output AC power.

Figure 6 is a table of conditions that organizes details of controls that are to be carried out primarily by an instantaneous power failure controller.

Fig. 7 is a graph illustrating conceptually a fixed output objective value according to a second embodiment.

Figure 8 is a schematic diagram illustrating functional units of a controller according to the second embodiment.

Figure 9 is a general diagram illustrating a configuration of an air conditioner.

Description of realizations

Hereinafter, embodiments of the present invention are described, with reference to the drawings. Note that the embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, the application of the present invention or the use of the present invention.

«First realization»

<General idea>

Figure 1 is a block diagram of a motor drive system (100) including an Energy Converter (20) according to the first embodiment. The motor drive system (100) of Figure 1 includes a motor (11) and the Power Converter (20).

The motor (11) is a three-phase brushless DC motor. Although not shown, the motor (11) includes, for example, a stator, a rotor and a Hall effect sensor. The stator includes multiple drive coils. The rotor includes a permanent magnet. The Hall effect sensor is used to detect a position of the rotor with respect to the stator.

Note that the motor (11) according to this first embodiment is a drive source for a compressor (72) included in an air conditioner (70) in FIG. 9. FIG. 9 is a general diagram illustrating a configuration of the air conditioner. air (70). As illustrated in Figure 9, an outdoor unit (71) includes the compressor (72) compressing a coolant, and the engine (11). The outdoor unit (71) also includes: a

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four-way switching valve (73) that switches a flow of refrigerant; an outdoor heat exchanger (74) that exchanges heat between the refrigerant and the outdoor air; an expansion valve (75) that decompresses the refrigerant; an outdoor fan (76) that supplies outdoor air to the outdoor heat exchanger (74), and a fan motor (77). An indoor unit (80) includes: an indoor heat exchanger (81) that exchanges heat between the refrigerant and indoor air; an indoor fan (82) that blows the air after heat exchange to the interior of the room; and a fan motor (83).

The Power Converter (20) is connected to the motor (11) and to a commercial power supply (91) by means of multiple harnesses. The Power Converter (20) converts input AC power, provided from the commercial power supply (91), into output AC power (SU, SV, SW), and supplies the output AC power converted to the motor (eleven). In this case, the commercial power source (91) is an AC power source. Such characteristics make it possible to operate the motor (11).

Note that the first embodiment has, as an example, a case in which the commercial power source (91) is a single-phase power source.

<Power converter configuration>

The Power Converter (20) mainly includes: a filter (21); a rectifier (22); a relay (23) of the main power supply; an input voltage detector (24); a power factor corrector (25); an output voltage detector (27); an energy converter (28); a current detector (29); a power factor correction actuator (30); and a controller (31).

-Filter-

The filter (21) is located between the commercial power supply (91) and the rectifier (22). The filter (21) is a low pass filter that includes a coil (21a) and a capacitor (21b), and reduces the high frequency noise, generated by the power factor corrector (25) and the power converter ( 28), which accidentally enters the commercial power supply (91).

-Rectifier-

The rectifier (22) is connected to a stage subsequent to the filter (21). The rectifier (22) includes four diodes (22a, 22b, 22c, 22d).

Specifically, the cathode terminals of the diodes (22a 22c) are connected to a power supply line (41). The anode terminals of the diodes (22b, 22d) are connected to a line (42) of GND. A connection point between the anode terminal of the diode (22a) and the cathode terminal of the diode (22b) and another connection point between the anode terminal of the diode (22c) and the cathode terminal of the diode (22d) are each connected to a different one of the outputs of the commercial power supply (91).

As illustrated in Figure 2, the rectifier (22) performs full wave rectification in an input AC from the commercial power source (91), and outputs the rectified input AC. Figure 2 illustrates temporary changes in: rectified voltage (i.e., an input voltage) (V1); peak amplitude (V11) of the input voltage (V1); entry detection period that will be discussed later; and detection result (Vca_peak) by the input voltage detector (24).

For ease of description, the input AC voltage is referred to herein as "commercial voltage (V0)".

-Main power supply relay-

The main power supply relay (23) is connected in series, in the power supply line (41), between the rectifier (22) and the power factor corrector (25). The main power supply relay (23) is normally a closed contact. The main power supply relay (23) is opened to stop the power supply from the commercial power supply (91) to the motor (11), in the case where, for example, the motor (11) has to stop being in motion urgently.

Examples of such a case include cases in which the compressor (72) generates an abnormally high pressure and the motor (11) receives an excessively large amount of current.

Note that the main power supply relay (23) may be located in a stage before the rectifier (22), instead of a step subsequent to the rectifier (22).

-Input voltage detector-

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The input voltage detector (24) detects the voltage (V1) that is output from the rectifier (22) as the input voltage to the power factor corrector (25).

Specifically, as illustrated in Figures 1 and 3, the input voltage detector (24) mainly includes two resistors (24a, 24b) connected in series with each other, a peak holding circuit (24c), and the controller (31) which functions as a sampler (31a) of input voltage. The two resistors (24a, 24b) are provided between the main power supply relay (23) and the power factor corrector (25), and are connected at the outputs of the rectifier (22). A voltage value at the connection point between the resistors (24a, 24b) is introduced into the peak holding circuit (24c). As illustrated in Figure 2, the peak holding circuit (24c) maintains a peak amplitude (V11), which represents the maximum value of the input voltage (V1), during a given period of time. This peak amplitude (V11) is input to the controller (31), sampled and converted from analog to digital by the input voltage sampler (31a) during an input detection period as illustrated in Figure 2 , and is identified by the input voltage detector (24) as the detection result (Vca_peak).

In this case, Figure 3 schematically illustrates the functional units of the controller (31) according to the first embodiment.

Further, Figure 2 illustrates a case in which an input detection period, which represents a detection period of the input voltage detector (24), is longer than a period (i.e., power frequency) in the that the input voltage (V1) reaches the maximum value.

-Corrector of power factor-

As illustrated in Figure 1, the power factor corrector (25) is connected through the main power supply relay (23) to the outputs of the rectifier (22). The power factor corrector (25) is a power factor correction circuit, and performs a power factor correction operation by raising and flattening the input voltage (V1).

Specifically, the power factor corrector (25) according to the first embodiment includes a three-phase step-up converter and a smoothing capacitor (26). In this case, the boost converter is a three-phase interleaved converter. More specifically, the power factor corrector (25) includes three reactors (L25a, L25b, L25c), three switching devices (Q25a, Q25b, Q25c), three resistors (R25a, R25b, R25c), three diodes (D25a, D25b, D25c) and a flattening capacitor (26).

The reactor (L25a) is connected in series in the power supply line (41). By using the input voltage (V1) as electrical power, the reactor (L25a) converts the input voltage (V1) into magnetic flux energy and stores the magnetic flux energy. An inductance value of the reactor (L25a) is appropriately determined based on, for example, a current value flowing through the power supply line (41), and a switching frequency of the switching device (Q25a).

The switching device (Q25a) is an isolated gate bipolar transistor n-ch, and connected in parallel to the reactor (L25a). The switching device (Q25a) switches between energy accumulation and discharge, based on the input voltage (V1), inside and outside the reactor (L25a). The switching on and off of the switching device (Q25a) is controlled by the power factor correction actuator (30).

The resistor (R25a) is a shunt resistor for detecting a PFC current (Ipfc) flowing through the switching device (Q25a), and connecting between the switching device (Q25a) and the line (42) of the GND . A voltage (Vdl) in the resistance (R25a) is converted from analog to digital, and then it is introduced in the controller (31) that functions as a PFC current calculator (31b) as seen in figure 3. voltage (Vdl) is used to calculate the PFC current (Ipfc). The PFC current (Ipfc) is used to control the actuation of the power factor corrector (25). This is to supply stable power to a stage subsequent to the power factor corrector (25) although the output voltage (V2) fluctuates to some extent. It is determined that the resistance of the resistance (R25a) is an appropriate value that does not impede an operation by the power factor corrector (25) to raise a voltage.

Note that, in Figure 1, the voltage (Vdl) in the resistor (R25c) alone is input to the controller (31). The voltages (Vdl) in the resistors (R25a, R25b) are also introduced in the controller (31).

The diode (D25a) is provided close to a reactor outlet (L25a), and is connected in series in the power supply line (41). Specifically, the diode (D25a) has an anode terminal provided further downstream in the direction of current flow than a connection point between the reactor (L25a) and the switching device (Q25a). The diode (D25a) allows current to flow only from the reactor (L25a) to the energy converter (28).

The flattening capacitor (26) is, for example, an electrolytic capacitor. A capacitor is provided

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of flattening (26) in common to the elevator converters for all phases. The flattening capacitor (26) is provided close to the outputs of the reactors (L25a, L25b, L25c), and connected in parallel to the switching devices (Q25a, Q25b, Q25c). The flattening capacitor (26) generates a direct current (DC) voltage having a relatively low corrugation component, charging itself with energy released from the reactors (L25a, L25b, L25c) and discharging the energy from itself.

An elevation operation of this type (ie, the power factor correction operation) is described by the power factor corrector (25), with reference to a step-up converter for a phase as an example. First, when the switching device (Q25a) is turned on, a current path is formed in the order of the power supply line (41), the reactor (L25a), the switching device (Q25a), the resistance (R25a) and line (42) of GND. The PFC current (Ipfc) flows in this order. Next, the PFC current (Ipfc) flows into the reactor (L25a) so that the reactor (L25a) is charged with energy. Then, when the switching device (Q25a) is turned off, the current path is cut by the switching device (Q25a). Accordingly, a current equivalent to the amount of energy stored inside the reactor (L25a) flows through the diode (D25a) into the flattening capacitor (26). As a result, the voltage in the flattening capacitor (26) increases.

Note that the boost converters for the other two phases are connected in parallel to the boost converter for the first phase, and the operations of the previous converters are similar to the operation of the last converter.

The number of the constituent elements such as the reactors (L25a, L25b, L25c) in the power factor corrector (25) is an example, and will not be limited as described above. In addition, instead of the resistors (R25a, R25b, R25c), a current sensor not shown can detect the PFC currents (Ipfc).

-Detector output voltage-

The output voltage detector (27) detects the output voltage (V2).

As illustrated in Figures 1 and 3, the output voltage detector (27) mainly includes: two resistors (27a, 27b) connected in series with each other; and the controller (31) that functions as an output voltage sampler (31c). The two resistors (27a, 27b) are provided between the power factor corrector (25) and the power converter (28), and are connected in the flattening capacitor (26). A voltage (V21) at a connection point between the resistors (27a, 27b) is input to the controller (31), sampled and converted from analog to digital by the output voltage sampler (31c) for a period of time. output detection, and is identified by the output voltage detector (27) as the result of the detection (Vcc) of the output voltage (V2).

The output detection period is shorter than the input detection period which is a detection period by the input voltage detector (24). For example, the output detection period may be approximately 10 ms when the input detection period is approximately 1 s.

-Converter of energy-

The power converter (28) is connected to an output of the power factor corrector (25) in parallel to the reactors (L25a, L25b, L25c). When the output voltage (V2) is received from the power factor corrector (25), the power converter (28) generates the output AC power (SU, SV, SW).

The power converter (28) includes an inverter circuit and an inverter actuator none of which is shown. The inverter circuit includes, for example, two or more of the following: power devices each of which is a bipolar isolated gate transistor; and free-flowing diodes each connected in inverse manner to a corresponding one of the power devices. The inverter actuator is, for example, an integrated circuit, and is connected to a door terminal of each power device. Based on a motor control signal (Pwm) to be output from the controller (31), the inverter drive controls the application of a gate voltage to each power device to turn the power device on and off, and causes that the inverter circuit generates the output AC power (SU, SV, SW).

-Detector of current-

The current detector (29) detects a value of an input current (Im) flowing to the power factor corrector (25). The input current (Im) flows from the commercial power supply (91) through the power supply line (41), and the power converter (28), into the motor (11). The input current (Im) then flows back to the power converter (28), through the GND line (42), into the power factor corrector (25).

As illustrated in FIGS. 1 and 3, the current detector (29) mainly includes, for example, a

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bypass resistor (29a) connected in series on line (42) of GND, and controller (31) which functions as an input current calculator (31d). A voltage (Vd2) in the shunt resistor (29a) is input to the controller (31), and sampled and converted from analog to digital by the input current calculator (31d) for a predetermined sampling period. The voltage (Vd2) is used for the calculation of the input current (Im).

-Adjustment of power factor correction-

The power factor correction actuator (30) is connected to the controller (31) and the gate terminals of the switching devices (Q25a, Q25b, Q25c). The power factor correction actuator (30) is, for example, an integrated circuit. Based on the PFC drive command signal (Cpfc) from the controller (31), the power factor correction actuator (30) controls the application of a gate voltage to each of the switching devices (Q25a, Q25b, Q25c) to turn on and off the power factor corrector (25).

Specifically, when the power factor corrector (25) is turned on for the power factor correction operation, the power factor correction actuator (30) outputs gate control signals (G1, G2, G3) to the respective switching devices (Q25a, Q25b, Q25c) so that the gate control signals (G1, G2, G3) repeatedly switch on and off the switching devices (Q25a, Q25b, Q25c) in a short period of time. On the contrary, when the power factor corrector (25) is turned off so that the power factor correction operation is stopped, the power factor correction actuator (30) outputs gate control signals (G1, G2). , G3) to the respective switching devices (Q25a, Q25b, Q25c) so that the gate control signals (G1, G2, G3) leave all the switching devices (Q25a, Q25b, Q25c) turned off.

-Controller-

The controller (31) includes a memory and a central processing unit (CPU). Depending on various programs stored in the memory, the controller (31) operates like the previous units as illustrated in Figure 3: namely, the input voltage sampler (31a), the PFC current calculator (31b); the output voltage sampler (31c); and the input current calculator (31d). In addition, the controller (31) functions as a motor drive controller (31e).

The motor drive controller (31e) determines the motor control signal (Pwm) based on rotor position information in the motor (11), and outputs the motor control signal (Pwm) determined to the inverter drive of the motor. power converter (28). The rotor position information includes, for example, the detection result by the Hall effect sensor in the motor (11), and the input current (Im) which is the result of detection by the current detector (29). . In addition, while the motor (11) is running, the motor drive controller (31e) performs a feedback control in the motor drive (11) using, for example, the rotor position information and a detection result. in a moment (Vca_pico, Vcc) for each one of the detectors (24, 27).

In addition, the controller (31) according to this first embodiment performs a control for the power factor corrector (25). The control includes: on-off control of the power factor corrector (25) when the motor (11) is running at a regular speed; variable control of the output target value (Vcc_ref) which indicates a target value of the output voltage (Vcc) to be emitted by the power factor corrector (25); and on-off control of the power factor corrector (25), associated with the occurrence of instantaneous voltage drop or instantaneous power failure.

The on-off control of the power factor corrector (25) performed when the motor (11) is running at a regular speed involves turning on and off the power factor corrector (25), based on, for example, the current input (Im), when there is no instantaneous voltage drop or instantaneous power failure. In the control, for example, the power factor corrector (25) turns on when the input current (Im) exceeds a first threshold value, and turns off when the input current (Im) drops below a second value threshold that is below the first threshold value. Instead of the control technique based on the input current (Im), the following control techniques can be adopted: a control technique based on the power output level from the power factor corrector (25); and a control technique to turn on the power factor corrector (25) as soon as the motor (11) is started.

In the following, the variable control of the target output value (Vcc_ref) and the on-off control of the power factor corrector (25), associated with instantaneous voltage drop or instantaneous power failure, are described in detail.

<Variable control of target output value>

This control is performed by the controller (31) that functions as a determinant (31f) of target value.

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Figure 4 conceptually illustrates the variable output target value (Vcc_ref) according to this first embodiment. In figure 4, the abscissa represents the interval of a predictive variation in the commercial voltage (V0), and the ordinate represents (i) a detection result (Vca_peak) by the input voltage detector (24) for each commercial voltage (V0) and (ii) a target output value (Vcc_ref). As illustrated in FIG. 4 and is represented by the expression (1) below, the objective value determiner (31f) determines, as the target output value (Vcc_ref), the result of adding a constant elevation amount ( Va) to a detection result at a time (Vca_peak) by the input voltage detector (24).

image 1

In other words, Figure 4 and Expression (1) show that, although the input voltage (V1) to the power factor corrector (25) varies, the target output value (Vcc_ref) is not always maintained in a determined value, and the output voltage (Vcc) from the power factor corrector (25) varies depending on the input voltage (V1). Specifically, Figure 4 illustrates that, as the commercial voltage (V0) becomes lower, the detection result (Vca_peak) by the input voltage detector (24) moves to a lower voltage, and the The resulting output target value (Vcc_ref) becomes smaller. On the contrary, as the commercial voltage (V0) becomes higher, the detection result (Vca_peak) by the input voltage detector (24) moves to a higher value, and the target output value ( Vcc_ref) resulting becomes greater. Such variable control of the target output value (Vcc_ref) is beneficial when the commercial voltage (V0) varies; that is, when "voltage variation of the power supply" occurs.

The voltage variation of the power supply is caused by various reasons. One such reason is that, when several devices operate simultaneously, by using the commercial power source (91) as the power source, the load on the capacity of the commercial power supply (91) exceeds a regular load. In such a case, excessive currents flow from the commercial power source (91) to each of the apparatuses, and the commercial power supply (91) can not withstand the influence of excessive currents. Therefore, the commercial tension (V0) falls from its reference value. Another reason is that when most of the appliances are not working, the load is lower than the regular load and, therefore, the commercial voltage (V0) rises above the reference value.

Such variation of power supply voltage may occur temporarily as well as permanently.

When the voltage variation of the power supply occurs, the detection result (Vca_peak) by the input voltage detector (24) also varies. For example, when the commercial voltage (V0) becomes lower with respect to the reference value if the output voltage (V2) from the power factor corrector (25) is constant regardless of the presence or absence of the variation of power supply voltage, the amount of power factor correction lift (25) increases compared to the case where the commercial voltage (V0) is the reference value. Then, the amount of energy that will be stored in the reactors (L25a, L25b, L25c) of the power factor corrector (25) increases and, naturally, the amount of currents flowing into the reactors (L25a) , L25b, L25c) and the switching devices (Q25a, Q25b, Q25c). As a result, they increase the power loss of the reactors (L25a, L25b, L25c) and the switching devices (Q25a, Q25b, Q25c).

Then, as represented by the expression (1) and illustrated in Figure 4, the target value determiner (31f) performs a control which involves keeping the amount of elevation (Va) of the power factor corrector constant (25). ), and determine the target output value (Vcc_ref) based on the detection result (Vca_peak) by the input voltage detector (24). Therefore, the elevation amount (Va) itself remains unchanged even if the voltage variation of the power supply occurs, so that the currents flowing through the switching devices (Q25a, Q25b, Q25c) remain approximately constant. Accordingly, the power loss of the reactors (L25a, L25b, L25c) and switching devices (Q25a, Q25b, Q25c), included in the power factor corrector (25), also remains approximately constant.

<On-off control by power factor corrector associated with instantaneous voltage drop and instantaneous power failure>

This control is carried out by the controller (31) that functions as a controller (31g) of instantaneous power failure equivalent to a controller.

In the above voltage supply voltage variation, a variation that occurs temporarily includes so-called instantaneous voltage drop and instantaneous power failure. Provoked, for example, by lightning, the instantaneous voltage drop is an instantaneous drop in commercial voltage (V0). Caused, for example, by lightning, instantaneous power failure is an instantaneous cut off of the commercial voltage supply (V0) to the Power Converter (20). The instantaneous drop or instantaneous power failure of the commercial voltage (V0)

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lasts, for example, from 10 ms to 100 ms.

For ease of explanation, instantaneous voltage drop and instantaneous power failure are referred to collectively herein as "instantaneous power interference".

In this case, a case is studied in which instantaneous power interference occurs in the commercial power source (91) while the power factor corrector (25) is performing the power factor correction operation. In this case, although the power factor corrector (25) is performing the power factor correction operation, the output voltage (V2) from the power factor corrector (25) decreases with a decrease in power factor correction (25). the input voltage (V1) to the power factor corrector (25). In the instantaneous power interference, the commercial voltage (V0) drops or the power supply is stopped for a very short period of time, as described above, so that the commercial power supply (91) is recovered in, for example, from 10 ms to 100 ms. In this case, the power factor corrector (25) raises the input voltage (V1) while the output voltage (V2) from the power factor corrector (25) itself has not reached the target output value (Vcc_ref). The resulting output voltage (V2) may increase suddenly and transiently. Then, an excessive current flows through the switching devices (Q25a, Q25b, Q25c) of the power factor corrector (25) to generate heat, possibly causing the fault (i.e., the so-called transient heat fault) of the switching devices (Q25a, Q25b, Q25c). The selection of the switching devices (Q25a, Q25b, Q25c) can be made in view of the excessive current; however, the selected switching devices (Q25a, Q25b, Q25c) tend to be large, which inevitably increases their costs.

As illustrated in FIG. 5, if the occurrence of an instantaneous power interference at the commercial power source (91) is determined (section B) while the power factor corrector (25) is performing the correction operation of power factor (section A), the instantaneous power failure controller (31g) according to this first embodiment turns off the switching devices (Q25a, Q25b, Q25c) so that the power factor correction operation is stopped (section C ). In particular, as illustrated in section C, the instantaneous power failure controller (31g) stops the power factor correction operation by the power factor corrector (25) when the power supply is recovered ( 91) commercial.

In this case, Figure 5 is a timing diagram illustrating temporary changes in: the input voltage (V1); the detection results (Vca_peak, Vcc) by the input voltage detector (24) and the output voltage detector (27); the permission and the prohibition of a power factor correction operation by the power factor corrector (25); the PFC drive instruction signal (Cpfc); the output state of the power factor correction actuator (30); the PFC current (Ipfc); and the output AC power (SU, SV, SW).

Specifically, since the instantaneous power interference does not occur in section A of figure 5, the detection results (Vca_peak, Vcc) by the input voltage detector (24) and the output voltage detector (27) they remain, in general, constant. In section A, the controller (31) outputs the PFC drive command signal (Cpfc) to drive the power factor corrector (25). Based on the gate control signals (G1, G2, G3) from the power factor correction actuator (30), the power factor corrector (25) performs the power factor correction operation. Therefore, the PFC currents (Ipfc) flow through the switching devices (Q25a, Q25b, Q25c). In addition, the power converter (28) emits the output AC power (SU, SV, SW), which drives the motor (11). Therefore, the compressor (72) is driven, and the air conditioner (70) performs an air conditioning operation including, for example, cooling operation and heating operation.

The instantaneous power interference occurs when section A transits to section B in figure 5. In this case, in section B, an operation is performed to determine the presence or absence of instantaneous power interference.

In this case, it is described how to detect the instantaneous power interference with reference to figure 6. Figure 6 illustrates a table of conditions (Ta1) that organizes details of controls to be performed mainly by the controller (31g) of failure of instantaneous power. The table of conditions (Ta1) in figure 6 associates operation names (Tall), operating conditions (Ta12) and operation details (Ta13) with each other.

As an operation condition (Ta12) having the registration number "1" shown in Figure 6, the instantaneous power failure controller (31g) subtracts the detection result (Vcc) by the output voltage detector (27) to the target output value (Vcc_ref) determined based on the expression (1), in order to calculate a difference between a detection result (Vcc) at a time by the output voltage detector (27) and the target output value (Vcc_ref). As represented by expression (2) below, if the difference is greater than a predetermined difference (DIF), the instantaneous power failure controller (31g) determines the occurrence of instantaneous power interference:

image2

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wherein the predetermined difference (DIF) is appropriately determined based on, for example, the reference value of the commercial voltage (V0), and the capacitances of the flattening capacitor (26) and the switching devices (Q25a, Q25b, Q25c) .

In this case, moreover, a condition can be satisfied (the result of the detection (Vcc) by the output voltage detector (27) is greater than a predetermined lower limit (LVP)) (Vcc> LVP) so that the controller (31g) of instantaneous power failure can reliably determine that the power failure is not a common power failure but the instantaneous power interference. In common failure, the result of detection (Vcc) by the output voltage detector (27) remains lower for a time than the predetermined lower limit (LVP), and the output voltage (V2) from the corrector of power factor (25) becomes sufficiently low during the power failure. Therefore, although the power factor correction operation is immediately initiated when the commercial power supply (91) is recovered, there is no phenomenon in which the output voltage (V2) suddenly increases from the power factor corrector (25).

Further, in this first embodiment, the condition is satisfied (the input detection period of the input voltage detector (24) is longer than the output detection period of the output voltage detector (27)) as described earlier. This is to reliably determine if instantaneous power interference has occurred. Specifically, although the peak amplitude (V11) of the input voltage (V1) actually falls instantaneously due to the occurrence of instantaneous power interference, a phenomenon occurs to show that the detection result itself ( Vca_peak) by the input voltage detector (24) does not fall to the degree to which the occurrence of the instantaneous power interference is determined, since the input detection period is longer than the output detection period. Meanwhile, the result of the detection (Vcc) by the output voltage detector (27) drops almost as low as the actual output voltage (V2). When the instantaneous power interference occurs, as opposed to the case where the instantaneous power failure does not occur, the difference between the target output value (Vcc_ref) and the detection result (Vcc) by the voltage detector output (27) is greater than or equal to the predetermined difference (DIF). In this case, the target output value (Vcc_ref) is the sum of the detection result (Vca_peak) by the input voltage detector (24) and the amount of elevation (Va). As a result, the instantaneous power interference controller (31g) can reliably determine the instantaneous power interference while performing variable control of the target output value (Vcc_ref).

Note that if the condition for the predetermined difference (DIF) is satisfied or not, if the result of the detection (Vcc) by the output voltage detector (27) is smaller than the predetermined lower limit (LVP) (Vcc < LVP) as an operation condition (Ta 12) having the registration number "2" shown in Figure 6, the instantaneous power failure controller (31g) determines that the output voltage (V2) is short. In this case, the main power supply relay (23) in Figure 1 opens, and the power converter (28) stops supplying the output AC power (SU, Sv, SW) to the motor (11). ). Accordingly, the compressor (72) stops running, and the air conditioner (70) stops the air conditioning operation. In this case, for example, on the display screen of a remote controller (not shown) for the air conditioner (70), a message appears to indicate the anomaly of the output voltage (V2).

After determining the occurrence of the instantaneous power interference in section B in figure 5, the instantaneous power failure controller (31g) then, in section C, switches (i) the state of the factor correction operation. power performed by the power factor corrector (25) from "allowed" to "prohibited", and (ii) the PFC drive instruction signal (Cpfc) from "actuate" to "stop". The power factor correction actuator (30) then stops the emission of the gate control signals (G1, G2, G3) to the power factor corrector (25), and the devices (Q25a, Q25b, Q25c) of Switching of the power factor corrector (25) are switched off. The current paths in the switching devices (Q25a, Q25b, Q25c) are cut off, and the PFC currents (Ipfc) stop flowing. As a result, the power factor correction operation is stopped as shown in an operation detail (Ta13) having the registration number "1" in Figure 6.

Note that, in section C, only the power factor corrector (25) is turned off. The compressor (72) does not stop and continues to run since the output AC power (SU, SV, SW) is supplied to the motor (11). In this case, the input voltage (V1) enters the power converter (28) without being raised by the power factor corrector (25).

Assuming that, in section C, the instantaneous power interference has been exceeded and the commercial power supply (91) has recovered. As an operation condition (Ta12) having the registration number "3" shown in Figure 6, the instantaneous power failure controller (31g) determines the recovery of the commercial power supply (91) if satisfied. the following conditions: the result of the detection (Vcc) by the output voltage detector (27) is greater than the predetermined lower limit (LVP) (Vcc> LVP); and approximately 100 ms have passed since the onset of instantaneous power interference. When the commercial power supply (91) is recovered, the instantaneous power failure controller (31g) monitors whether the compressor (72) is running normally according to the motor drive (11) as shown in FIG.

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shows in an operation detail (Ta13) having the registration number "3" in figure 6. The instantaneous power failure controller (31g) then starts the measurement, from the recovery of the commercial power supply (91) , of a period of time in which the compressor (72) is running normally.

When section C transits to section D, assuming that the period of time that has been measured has reached a predetermined time period as shown in an operation condition (Ta12) having the registration number "4" in the figure 6. In this case, as shown in section D in figure 5 and an operation detail (Ta13) having the registration number "4" in figure 6, the power failure controller (31g) snapshot switches the state of the power factor correction operation performed by the power factor corrector (25) from "prohibited" to "allowed". Then, immediately after switching the status of the power factor correction operation to "allowed", the instantaneous power failure controller (31g) determines whether to actually perform the power factor correction operation, depending on, for example , the input current (Im). If it is determined to perform the power factor correction operation, the instantaneous power failure controller (31g) switches the PFC drive instruction signals (Cpfc) from "stop" to "drive". Therefore, the power factor correction actuator (30) resumes the emission of the gate control signals (G1, G2, G3), and the switching devices (Q25a, Q25b, Q25c) repeat the switching on and off. Accordingly, the switching devices (Q25a, Q25b, Q25c) initiate the conduction of the PFC currents (Ipfc), followed by the start of the power factor correction operation. The compressor (72) continues to run also in section D.

Note that if an abnormality is observed in the motor drive (11) from the recovery of the commercial power supply (91) over the predetermined time period, the controller (31) can turn off the source relay (23) of main power to stop the motor drive (11). In this case, the "anomaly" includes an overcurrent of the motor (11), for example.

A predetermined time period shorter than a time interval from the recovery of the commercial power supply (91) to the start of the ripple drop control is beneficially established. The ripple drop control involves reducing the ripple components of the voltage in the flattening capacitor (26).

When the instantaneous power interference occurs in this first embodiment, the power factor corrector (25) is temporarily turned off to suspend the power factor correction operation. During the suspension, the input voltage (V1), which is not high, is applied to the flattening capacitor (26). Despite the suspension of the power factor correction operation, the instantaneous power interference, which lasts a very short period of time, allows the load (i.e., the drive motor (11)) in the converter to energy (28) remains relatively unchanged before and after the power factor correction operation. As a result, depending on the level of the charge, there may be an increase in the undulation components of the voltage in the flattening capacitor (26), causing the life of the flattening capacitor (26) to be reduced. However, when the corrugation components increase, the controller (31) performs a control in, for example, 30 s after the recovery of the commercial power supply (91) to, for example, decrease the speed of the motor (11). ) to make the corrugation components fall (i.e., ripple fall control), thereby reducing the load. However, the ripple drop control would also cause a decrease in the drive efficiency of the compressor (72), which, inevitably, results in a decrease in the performance of the air conditioner (70). Therefore, when the commercial power supply (91) is recovered in this first embodiment, the power factor corrector (25) is turned on to resume the power factor correction operation before the start of the ripple fall control. This satisfactorily minimizes the decrease in air conditioning performance.

Note that the predetermined time period can take a fixed value, as well as a determined variable value depending on the period and the degree of the instantaneous power interference.

Note that, as an example, Figure 5 illustrates a case in which there is a timing difference between (i) when the status of the power factor correction operation switches from "prohibited" to "allowed" and (ii) when the power factor correction operation actually resumes. This shows that switching the state from "prohibited" to "allowed" does not immediately start the power factor correction operation. Therefore, if the condition was already correct to actually carry out the power factor correction operation when the status of the power factor correction operation switches from "prohibited" to "allowed", the controller (31g) of Instantaneous power failure can immediately turn on the power factor corrector (25).

<Effects of the first performance>

In the Power Converter (20) according to this first embodiment, the switching devices (Q25a, Q25b, Q25c) in the elevator power factor (25) corrector are turned off when instantaneous power interference occurs, and the operation of Power factor correction (the lifting operation) is suspended. When

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recover the commercial power supply (91), the power factor correction operation is suspended. Therefore, in the power factor corrector (25), the current paths that include the switching devices (Q25a, Q25b, Q25c) are cut off. The cutting of the current paths limits a temporary sudden increase of the output voltage (V2) from the power factor corrector (25), due to the power factor correction operation performed when the power supply is recovered ( 91), and reduces an excessive amount of current flowing in the switching devices (Q25a, Q25b, Q25c). Such characteristics make it possible to limit the malfunctioning of the switching devices (Q25a, Q25b, Q25c), contributing to a reduction of the switching devices (Q25a, Q25b, Q25c) in size and cost.

Further, in the Power Converter (20) according to this first embodiment, the instantaneous power failure controller (31g) can determine the occurrence of the instantaneous power interference if the difference between the target output value (Vcc_ref) and the result of the detection (Vcc) by the output voltage detector (27) is greater than the predetermined difference (DIF). Such a feature allows the instantaneous power failure controller (31g) to easily determine whether instantaneous power interference has occurred.

In addition, when the instantaneous power interference occurs, both the actual input voltage (V1) and the actual output voltage (V2) decrease. Meanwhile, in this first embodiment, the input detection period is longer than the output detection period. If the instantaneous power interference has occurred, the detection result (Vca_peak) by the input voltage detector (24) is of higher value than the result of the detection (Vcc) by the output voltage detector (27). ). Therefore, the difference between the target output value (Vcc_ref) and the result of detection (Vcc) by the output voltage detector (27) is greater than the predetermined difference (DIF). In this case, the target output value (Vcc_ref) is the sum of the detection result (Vca_peak) by the input voltage detector (24) and the amount of elevation (Va). As a result, the instantaneous power failure controller (31g) can reliably determine the instantaneous power interference even when variable control is performed on the target output value (Vcc_ref).

Furthermore, in this first embodiment, the power factor corrector (25) is turned off when the instantaneous power interference occurs; however, the compressor (72) continues to run. A feature of this type allows a user to be comfortable in a room conditioned by air through the air conditioner (70).

Furthermore, in this first embodiment, the power factor corrector (25) can resume the power factor correction operation when the compressor (72) is running normally.

Further, in this first embodiment, the power factor corrector (25) is allowed to perform a power factor correction between the recovery of the commercial power source (91) and the start of the ripple fall control. Such characteristics minimize a decrease in performance, of the air conditioner (70), due to the ripple fall control.

<Modified example 1 of the first embodiment>

As shown in Figure 4 and Expression (1), the target output value (Vcc_ref) of the power factor corrector (25) is determined by the sum of the detection result (Vca_peak) by the input voltage detector ( 24) and the constant elevation amount (Va).

However, the target output value (Vcc_ref) may vary depending on the detection result (Vca_peak) by the input voltage detector (24). The instantaneous power failure controller (31g) can determine the target output value (Vcc_ref) based on a technique, different from those obtained by means of FIG. 4 and expression (1).

<Modified example 2 of the first embodiment>

The input voltage detector (24) can also sample, instead of the peak amplitude (V11) of the input voltage (V1), values such as an effective value and an average value of the commercial voltage (V0) or the input voltage (V1), based on the input detection period.

In the above statements, the entry detection period is longer than the exit detection period; however, the input detection period does not have to be longer than the output detection period if the instantaneous power interference is satisfactorily detected without difficulty.

<< Second realization >>

This second embodiment describes a case in which the target output value (Vcc_ref) is a fixed value. Next, different characteristics are described only from those of the first embodiment.

<How to determine the target output value>

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Figure 7 is a graph illustrating conceptually a fixed output target value (Vcc_ref) according to this second embodiment. In figure 7, the abscissa represents the interval of a predictive variation in the commercial voltage (V0), and the ordinate represents (i) a detection result (Vca_peak) by the input voltage detector (24) for a commercial voltage (V0) and (ii) a target output value (Vcc_ref). Figure 8 is a schematic diagram illustrating functional units of the controller (31) according to the second embodiment.

As illustrated in FIG. 7, the target output value (Vcc_ref) is previously set constant, despite the detection result (Vca_peak) by the input voltage detector (24). As an example, Figure 8 illustrates a case in which the controller (31) does not function as the target value determiner (31f) in the first embodiment.

The target output value (Vcc_ref) according to this second embodiment is determined based on the state of the commercial power source (91) in an environment in which the air conditioner (70) is installed. In particular, taking into account the circumstances (specifically, for example, the voltage variation of the power supply) of the countries in which the air conditioner is likely to be installed (70), the target output value (Vcc_ref) is determined preferably to be higher than the peak amplitude (V11) of the input voltage (V1) based on the commercial voltage (V0) of any commercial power source (91). This is because if an inversion occurs (the peak amplitude (V11) of the input voltage (V1) becomes higher than the target output value (Vcc_ref)), the power factor corrector (25) stops the elevation of the input voltage (V1) so that the power factor becomes lower.

<On-off control by the power factor corrector associated with the occurrence of instantaneous voltage drop and instantaneous power failure>

In a manner similar to the first embodiment, when instantaneous power interference including instantaneous voltage drop and instantaneous power failure is detected while the power factor corrector (25) is performing a power factor correction operation, the instantaneous power failure controller (31g) shuts off the switching devices (Q25a, Q25b, Q25c) so that the power factor correction operation is stopped. When the commercial power supply (91) is recovered, the power factor correction operation by the power factor corrector (25) is also suspended.

The mode of detecting the instantaneous power interference and the detailed operations of the instantaneous power failure controller (31g) are similar to those described in the first embodiment, and the description thereof will be omitted.

Note that, in the first embodiment, the condition is satisfied (the input detection period is longer than the output detection period) so that variable control is achieved at the target output value (Vcc_ref). The condition can be included as a condition for detecting the instantaneous power interference also in this second embodiment in which the target output value (Vcc_ref) is a fixed value. This is because the occurrence of instantaneous power interference is successfully detected without problems.

<Effects of the second embodiment>

In the Power Converter (20) according to this second embodiment, as well as the first embodiment, the switching devices (Q25a, Q25b, Q25c) in the elevator power factor (25) corrector are turned off when the power interference occurs. The power supply (91) is recovered instantaneously and the power factor correction operation (the lifting operation) is suspended. Therefore, in the power factor corrector (25), the current paths that include the switching devices (Q25a, Q25b, Q25c) are cut off. Although the target output value (Vcc_ref) is fixed, the cutting of the current paths limits a temporary sudden increase in the output voltage (V2), from the power factor corrector (25), due to the power factor correction operation performed when the commercial power supply (91) is recovered, and reduces an excessive amount of current flowing in the switching devices (Q25a, Q25b, Q25c). Such characteristics make it possible to limit the malfunctioning of the switching devices (Q25a, Q25b, Q25c).

<Modification of the second embodiment>

The energy converter (20) according to the second embodiment may include either the input voltage detector (24) or the output voltage detector (27). In this case, the operation condition (Ta12) having the registration number "1" in figure 6 is changed.

If the Power Converter (20) includes the input voltage detector (24), the input voltage detector (24) samples the value of the input voltage (V1) in a shorter period of time (e.g. 10 ms each time) than the input detection period according to the first embodiment, and obtains the sampled value as a result of detection. If the Power Converter (20) includes the output voltage detector (27), the output voltage detector (27) samples the value of the output voltage (V2) in one period (for example, 10 ms each time). )

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similar to the output detection period according to the first embodiment, and obtains the sampled value as a detection result. In this case, the instantaneous power interference controller (31g) can determine if instantaneous power interference has occurred and the commercial power supply (91) has been recovered, depending on how large or small the detection result is. by the input voltage detector (24) or the output voltage detector (27).

<< Other realizations »

The first and second embodiments may include the configurations below.

The parameter to be used to detect the instantaneous power interference need not be limited to the detection results by the input voltage detector (24) and the output voltage detector (27). Any parameter and detection technique can be adopted as long as the instantaneous power interference can be detected. Other parameters include the PFC current (Ipfc) and the input current (Im).

When the instantaneous power interference occurs, the compressor (72) may also stop running.

The condition in which the power factor correction operation is allowed for the power factor corrector (25) may be a condition other than the case where the compressor (72) continues in operation from the recovery of the power source. commercial feed (91) over the predetermined time period. For example, the power factor correction operation can be allowed when the PFC current (Ipfc) or the input current (Im) exceeds a predetermined value after the recovery of the commercial power supply (91).

In addition, the predetermined time period does not have to be shorter than the observed time interval until the onset of the ripple fall control. A predetermined time period longer than the time interval can be set.

If the air conditioner (70) (that is, more specifically, the compressor (72)) is running under overload when instantaneous voltage interference occurs, stopping the power factor corrector (25) decreases a factor of input power. As a result, an excessive amount of current inevitably flows into the rectifier (22) and the main power supply relay (23). In such a case, the ripple drop control can be performed almost simultaneously with the power factor corrector off control (25) in order to protect, for example, the rectifier (22). Such a feature limits the performance of the compressor (72) despite the fact that the power factor correction operation is stopped, which helps to limit the flow of the excessive amount of current into, for example, the rectifier. (22) Note that the overload condition of the compressor (72) occurs when the load (for example, the speed of rotation of the motor (11)) exceeds the reference value. The reference value includes, for example, the maximum value of the load (for example, the speed of rotation of the motor (11)) with which the compressor (72) can be operated normally with respect to the voltage, in the capacitor of flattening (26), observed when the power factor corrector (25) is stopped.

In addition, the motor (11) can also drive other units, such as the indoor fan (76) and the indoor fan (82), other than the compressor (72).

In addition, a rectifier circuit independent of the rectifier (22) can be connected to the commercial power supply (91), and the input voltage detector (24) can detect the output voltage from the rectification circuit.

Industrial applicability

As can be seen, the present invention is useful for an energy converter that includes a power factor correction, and an air conditioner equipped with the power converter.

Description of reference characters

20 Power converter 22 Rectifier

24 Input voltage detector

25 Power factor corrector

26 Flattening capacitor

5

10

fifteen

twenty

25

30

L25a, L25b, L25c Reactor

Q25a, Q25b, Q25c Switching device

27 Output voltage detector

28 Energy converter

31g Instantaneous Power Failure Controller (Controller)

70 Air conditioner 72 Compressor

91 Commercial power supply (AC power supply)

VI Input voltage

VII Peak amplitude V2 Output voltage

Vca_peak Detection result via input voltage detector Vcc Detection result via output voltage detector Vcc_ref Target output value (Target value of output voltage)

DIF Default difference

Claims (2)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 Power converter (20) that provides power to a compressor (72) in an air conditioning apparatus (70), the energy converter comprising: a rectifier (22) configured to rectify an alternating current (AC) input from an AC power source (91); a power factor corrector (25) including a reactor (L25a, L25b, L25c) and a switching device (Q25a, Q25b, Q25c) that switches between energy accumulation and discharge, based on an input voltage (V1) which is emitted from the rectifier (22), inside and outside the reactor (L25a, L25b, L25c), and configured to be able to perform a power factor correction operation by raising the input voltage (V1); an energy converter (28) connected to an output of the power factor corrector (25), and configured to generate output AC power (SU, SV, SW); Y a controller (31g) configured to control the power factor correction operation by the power factor corrector (25), characterized in that the power factor corrector (25) includes a flattening capacitor (26) provided close to a reactor outlet (L25a, L25b, L25c), and connected in parallel to the switching device (Q25a, Q25b, Q25c), and The controller (31g) is configured to: turn off the switching device (Q25a, Q25b, Q25c) so that the power factor correction operation is stopped, if instantaneous voltage drop or instantaneous power failure occurs in the AC power supply (91) while the power factor corrector (25) is performing the power factor correction operation; leaving the compressor (72) running without rest, if instantaneous voltage drop or instantaneous power failure occurs while the compressor (72) is running; leave the power factor correction operation stopped when the AC power supply (91) is recovered; Y allowing the power factor corrector (25) to perform the power factor correction operation, if the compressor (72) continues to run from the recovery of the AC power source (91) for a predetermined period of time; wherein the predetermined time period is shorter than a time interval from the recovery of the AC power source (91) to a start of control to drop a ripple component of a voltage on the smoothing capacitor ( 26). Energy converter according to claim 1, further comprising an output voltage detector (27) configured to detect an output voltage (V2) of the power factor corrector (25), wherein the controller (31g) is configured to determine the occurrence of instantaneous voltage drop or instantaneous power failure if a difference between (i) a target value (Vcc_ref) of the output voltage to be emitted by the factor corrector of power (25) and (ii) a result of the detection (Vcc) by the output voltage detector (27) is greater than a predetermined difference (DIF). Energy converter according to claim 2, further comprising an input voltage detector (24) configured to detect the input voltage (V1), in which the controller (31g) is configured to determine the target value (Vcc_ref) of the output voltage (V2), based on a detection result (Vca_peak) by the input voltage detector (24), and a detection period of the input voltage detector (24) is longer than a detection period of the output voltage detector (27). Energy converter according to claim 3, wherein the input voltage detector (24) is configured to display a peak amplitude (V11) of the input voltage (V1), and determine the sampled peak amplitude (V11) as the detection result (Vca_peak). 5. Power converter according to claim 1, further comprising an input voltage detector (24) configured to detect the input voltage (V1), in which the controller (31g) is configured to determine whether instantaneous voltage drop or instantaneous power failure has occurred, depending on how large or small the detection result is (Vca_pico) by the input voltage detector (24). 6. Power converter according to claim 1, wherein 15 the controller (31g) is configured to cause the factor correction operation to stop power and drop the ripple component of the voltage in the flattening capacitor (26), if instantaneous voltage drop or instantaneous power failure occurs while the compressor (72) is running under overload.